1. Field of the Invention
This invention relates to vacuum cleaners for household or industrial use for removing foreign matter, dust and debris from floor or carpet surfaces, and particularly those cleaners which provide compressed air means for dislodging or agitating the soil and conveying it toward the vacuum intake means.
2. Description of the Prior Art
An early patent in this art is Farnsworth U.S. Pat. No. 1,281,925 which describes a vacuum cleaner with an inlet opening and a suction-creating, motor/blower wheel or fan that conveys the soil-laden air from the floor or carpet to a porous cleaner bag or filter bag. A second porous cleaner bag or filter bag surrounds the first bag, and part of the air in the second bag is returned to the vicinity of the inlet opening where a blast of air is directed down into the inlet opening to dislodge or agitate the soil on the floor or in the carpet. Thus a partial air recirculating system is provided.
The Hornschuch et al. U.S. Pat. No. 3,161,900 describes a vacuum cleaning head for use with mining apparatus around mine shafts and drilling sites. The head is equipped with a high pressure air blast which is operable to impart a velocity to objects heavier than dust so that they may be collected by an integral vacuum device.
The Lake et al. U.S. Pat. No. 3,328,827 describes a hand-held, air-operated vacuum cleaner for use around gasoline stations that are equipped with high pressure air hoses for use in inflating automobile tires. Such a high pressure air hose is connected to this Lake vacuum cleaner, and the air pressure drives an air turbine that in turn drives a suction fan. The air turbine and the suction fan are both mounted on a common shaft. This vacuum cleaner has a suction head having outwardly disposed forced air discharge ports and a central suction passage.
The Hilbig U.S. Pat. No. 3,678,534 describes a vacuum system for cleaning some surfaces having insoluble dirt particles or coatings firmly attached thereto or embedded therein. One such surface is an acoustical panel having a honeycomb core covered on one side with a thin, imperforate facing sheet and on the other side by a similar facing sheet having a multiplicity of small perforations. The vacuum cleaner head has a high pressure air line with jets of air moving at supersonic speeds. The jet streams dislodge stubborn dirt particles for removal by a vacuum line communicating with the cleaner head.
The Mac Farland U.S. Pat. No. 3,825,972 describes a shag rug rake attachment for mounting on the cleaning nozzle of a vacuum cleaner for combing deep pile shag rugs.
The Haldeman U.S. Pat. No. 3,963,515 describes a conventional vacuum cleaner suction nozzle typically used for cleaning streets or carpets with a plurality of vortex generating air nozzles supported from the nozzle and directed downward ahead of the suction nozzle.
The Rose et al. U.S. Pat. No. 4,037,290 describes an institutional or commercial vacuum cleaner having a downwardly facing hood to form a travelling chamber. An air jet nozzle is positioned within the hood, and the nozzle is moved in a circular horizontal orbit by a variable speed motor. A pump is attached to the hood to maintain a vacuum therein.